User Notifications: Can't setup notification to SMS tmobile?

Brian - where your numbers recently ported in?  If so, it could take 7-14 days. 

If the numbers are not newly ported and you have isolated it to T-Mobile, please open a web case and support will contact t-mobile and resolve the issue. Put in your case that is specific to T-mobile and provide a few samples (date, time, texted number to, texted number from)

Kim 

Well, you can't even put in a number and assign it to Tmobile. In the dropdown there is AT&T, Sprint, etc. all the major carrier, but Tmobile is not on the list. I'm not sure what this has to do with the number being ported over.

Use email to SMS gateway provided by t-mobile: https://support.t-mobile.com/docs/DOC-3309

5105551212@tmoemail.net for example.